BUBBLE EFFECTS ON ION-EXCHANGE MEMBRANES - AN ELECTROCHEMICAL STUDY
作者:
XIONG, Y* ;JIALING, L;HONG, S
期刊:
Journal of Applied Electrochemistry ,1992年22(5):486-490 ISSN:0021-891X
通讯作者:
XIONG, Y
作者机构:
[XIONG, Y; JIALING, L; HONG, S] Laboratory of Membrane Electrochemistry, Department of Chemistry, Huazhong Normal University, Wuhan, China
通讯机构:
[XIONG, Y] H;HUAZHONG NORMAL UNIV,DEPT CHEM,MEMBRANE ELECTROCHEM LAB,WUHAN,PEOPLES R CHINA.
关键词:
Physical Chemistry;Electrochemical Study;Bubble Effect
摘要:
Bubble attachment on ion exchange membranes during electrolysis in chlor-alkali cells is of great concern because it has a marked influence on the cell voltage. This paper reports a method to investigate the bubble effect on membranes during electrolysis. The method uses conventional electrochemical linear sweep voltammetry (LSV) and a four electrode system.
语种:
英文
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MAXIMUM OVERLAP SYMMETRY MOLECULAR-ORBITAL MODEL
作者:
ZHAN, CG*
期刊:
International Journal of Quantum Chemistry ,1992年44(2):123-140 ISSN:0020-7608
通讯作者:
ZHAN, CG
作者机构:
[Chang–Guo Zhan; ZHAN, CG] Department of Chemistry, Central China Normal University, Wuhan 430070, The People's Republic of China
通讯机构:
[ZHAN, CG] C;CENT CHINA NORMAL UNIV,DEPT CHEM,WUHAN 430070,PEOPLES R CHINA.
会议名称:
3RD PRESIDENTS MEETING OF THE INTERNATIONAL SOC OF QUANTUM BIOLOGY AND PHARMACOLOGY
会议时间:
SEP 04-07, 1991
会议地点:
STANFORD UNIV, PALO ALTO, CA
摘要:
This paper provides a brief and systematic presentation of the basic principle and method of the maximum overlap symmetry molecular orbital (MOSMO) model and its application to simplification of molecular orbital calculation and to calculation of molecular structures and properties, together with some new results about the MOSMO calculation and new insights concerning the further extension of the principle and method. It has been shown that the theoretical method of the MOSMO model is very simple, reliable, and useful and can be employed to study the structure–property relation in even very large molecular systems. The numerical results obtained from the MOSMO calculation on various semiempirical molecular orbital approximation levels show that when the same parametrization, such as one of those employed in EHMO, CNDO/2, and HMO methods, is adopted, the MOSMOS are very close to the canonical molecular orbitals obtained from the customary LCAO method and the MOSMO calculation requires less computing time than does the LCAO method. The MOSMO calculation can be used for rapidly obtaining reasonably good molecular geometries, vibrational frequencies, and other properties of molecules by employing a simple improved semiempirical parametrization. Equilibrium geometries, vibrational frequencies, and other results are in good agreement with the experimental data and the results obtained from ab initio molecular orbital calculation. The basic calculational procedure of the MOSMO model can be extended further and has been employed to give some new results, to propose some new theoretical schemes and principles, and to introduce some new interesting theoretical problems that deserve to be studied further. Copyright © 1992 John Wiley & Sons, Inc.
语种:
英文
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5-甲硫基-3-N-苯基-2,3-2(H)-1,3,4,2-噻二唑磷茂啉的磷烯正离子的合成与表征
作者:
黄天宝;张景龄;湛昌国;张友杰
期刊:
中国科学:化学 ,1992年(10):1024-1030 ISSN:1674-7224
作者机构:
[黄天宝; 张景龄; 湛昌国; 张友杰] 华中师范大学
关键词:
磷烯正离子;摩尔电导;噻二唑磷茂啉
摘要:
本文首次合成了环中除氮外有硫直接与磷相连的新型5-甲硫基-3-N-苯基-2,3-2(H)-1,3,4,2-噻二唑磷茂啉的磷烯正离子,用化学反应、波谱性质、摩尔电导、扩展Hǖckel分子轨道计算法讨论和证明其结构,在研究它的亲核反应时,曾与非离子型化合物做了对比,还研究了它的新型亲电反应。
语种:
中文
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MOLECULAR EQUILIBRIUM GEOMETRIES AND VIBRATIONAL FREQUENCIES BY MAXIMUM OVERLAP SYMMETRY MOLECULAR-ORBITAL METHOD
作者:
ZHAN, CG*
期刊:
International Journal of Quantum Chemistry ,1992年41(6):773-783 ISSN:0020-7608
通讯作者:
ZHAN, CG
作者机构:
Department of Chemistry, Central China Normal University, Wuhan, 430070, The People's Republic of China
通讯机构:
[ZHAN, CG] C;CENT CHINA NORMAL UNIV,DEPT CHEM,WUHAN 430070,PEOPLES R CHINA.
摘要:
It is demonstrated that the maximum overlap symmetry molecular orbital method can be used for optimization of molecular geometries and calculation of vibrational frequencies by adding a two‐body repulsive energy term and a modification of the Wolfsberg–Helmholz formula. The obtained equilibrium geometries and vibrational frequencies are on the whole in good accordance with experimental data, which shows that the basic idea using the method to optimize molecular geometries and to calculate vibrational frequencies is reasonable. Copyright © 1992 John Wiley & Sons, Inc.
语种:
英文
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杰出的化学家、教师和诗人——罗德·霍夫曼
作者:
刘范;李静
期刊:
化学通报 ,1992年(07):57-60 ISSN:0441-3776
作者机构:
武昌华中师范大学化学系;Dept.of Chemistry Rutgers Uni.;430070;Camden;NJ 08102
摘要:
<正> 罗德·霍夫曼(Roald Hoffmann)的名字将永载化学史册。在年仅28岁时,他的名字已为大学生所熟悉了,他就是“伍德沃德-霍夫曼
语种:
中文
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Polarographic determination of atmospheric nitrogen oxides
作者:
LU, GH* ;HE, ZK;LIU, YL
期刊:
Talanta ,1992年39(2):123-126 ISSN:0039-9140
通讯作者:
LU, GH
作者机构:
[LIU, YL; LU, GH; HE, ZK] SHAN DONG LIN YI EDUC COLL,JI NAN,PEOPLES R CHINA.;[LU, GH] CENT CHINA NORMAL UNIV,DEPT CHEM,WUHAN 430070,PEOPLES R CHINA.
通讯机构:
[LU, GH] C;CENT CHINA NORMAL UNIV,DEPT CHEM,WUHAN 430070,PEOPLES R CHINA.
摘要:
A new polarographic method is described for the determination of nitrite/nitrogen oxides. The nitrite is first diazotized with p-aminobenzoic acid, followed by coupling to 8-hydroxyquinoline to produce an azo dye. This azo dye is adsorbable on a mercury drop electrode and its reduction is reversible. The linear response range is 6 x 10(-9)-3 x 10(-7) g/ml. The detection limit is 4 x 10(-9) g/ml. This method has been applied to the determination of nitrogen oxides in the air.
语种:
英文
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一种方便的氯化苄制备的中控方法
作者:
邹从炎;杨自善;靳志林;白一穷
期刊:
精细化工 ,1992年(1):50-52 ISSN:1003-5214
作者机构:
武汉市华中师范大学化学系
关键词:
吸收瓶;控方;增重速度;氯化苄;水吸收
摘要:
介绍了氯化苄制备过程的一种新的中控方法——水吸收HCl称重法,采用它可随时对反应体系的氯化程度进行测定,简便、准确、快速。
语种:
中文
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从植物中寻找农药活性物质
作者:
朱正方
期刊:
天然产物研究与开发 ,1992年(3):73-88 ISSN:1001-6880
作者机构:
华中师范大学农药研究所 武昌 430070
关键词:
植物;农药活性有效母体;新农药
摘要:
从植物中寻找农药活性物质,判明结构,使之成为创新类型农药有效母体,是创制新农药品种的重要途径之一,受到当今全世界农药界的广泛重视。本文综合性介绍植物与农药的关系,该交叉学科研究的一般程序和方法以及通过对有效母体的结构改造,构一效关系的研究,创制新农药的研究过程。
语种:
中文
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Semiconductive properties and photoelectrochemistry of iron oxide electrodes—IX. Photoresponses of sintered Zn-doped oxide electrode
作者:
CAI, SM* ;JIANG, DL;ZHANG, JJ;TONG, RT;JIN, SX;...
期刊:
Electrochimica Acta ,1992年37(3):425-428 ISSN:0013-4686
通讯作者:
CAI, SM
作者机构:
HEBEI NORMAL UNIV,DEPT CHEM,SHIJIAZHUANG 050016,PEOPLES R CHINA.;HUAZHONG NORMAL UNIV,DEPT CHEM,WUNAN 430070,PEOPLES R CHINA.;HEBEI TEACHERS UNIV,DEPT CHEM,SHIJIAZHUANG 050016,PEOPLES R CHINA.;UNIV TOKYO,DEPT SYNTHET CHEM,TOKYO 113,JAPAN.;[CAI, SM] BEIJING UNIV,DEPT CHEM,BEIJING 100871,PEOPLES R CHINA.
通讯机构:
[CAI, SM] B;BEIJING UNIV,DEPT CHEM,BEIJING 100871,PEOPLES R CHINA.
关键词:
iron oxide;photocurrent;photovoltage waveforms;semiconductive characteristics;zinc doping.
摘要:
On the basis of our previous report [S. Cai, T. Lu and M. Zhou, Electrochim. Acta 36 1585 (1991)] that the sintered Zn-doped iron oxide electrode showed strange photoresponses of n-type semiconductive characteristics at more positive potential, p-type semiconductive characteristics at more negative potential and both n-type and p-type semiconductive characteristics at intermediate potential, a primary mechanism for this phenomenon is presented in this paper. The energy band diagram at one electrode with n-type and p-type semiconductors is given. By using the theoretical model, the above phenomenon can be explained. © 1991.
语种:
英文
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香笔菌气味成分的GC/MS研究
作者:
吴田捷;黄天宝;刘翠华;古练权;纪大千;...
期刊:
华中师范大学学报(自然科学版) ,1992年(03):66-68 ISSN:1000-1190
作者机构:
华中师范大学分析测试中心有机合成所;中国科学院昆明植物研究所
关键词:
香笔菌;气味成分;色谱/质谱分析
摘要:
首次报道用GC/MS研究香笔菌气味成份的结果,通过利用GC/MS技术,共鉴定出其中的29种成分,有一些化合物在该属中为首次发现。
语种:
中文
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介绍几种室内测定杀线虫剂活性的简易方法
作者:
万树青
期刊:
植物保护 ,1992年(06):44 ISSN:0529-1542
作者机构:
华中师范大学农药化学研究所 武昌 430070
摘要:
<正> 在创制新的杀线虫剂过程中,室内初筛是必不可少的一环。根据杀线虫剂作用方式,(如内吸,触杀或熏蒸),可进行以下几种活性测试工作。 1.土壤淋浴法 选择2-3种禾谷类或其它敏感植物,如高梁种植在装55cm3壤土的一种钵内,待长至6-7cm高,每钵土用2ml 10ppm试验化
语种:
中文
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气相色谱-质谱联用法测定吸毒者尿中吗啡浓度
作者:
徐友宣;朱绍棠;张长久;吴筠;张友杰
期刊:
高等学校化学学报 ,1992年13(5):608-610 ISSN:0251-0790
作者机构:
[徐友宣; 朱绍棠; 张长久; 吴筠] 国家体委运动医学所兴奋剂检测中心;[张友杰] 华中师范大学
关键词:
吗啡;吸毒者
摘要:
本文建立了测定吸毒者尿中吗啡浓度的方法,样品经酸解、醚洗、碱化及溶剂提取后,用MSTFA衍生化,最后用GC/MS(SIM)法分析,以内标法定量。
语种:
中文
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2-氨基-4,6二取代嘧啶的合成
作者:
薛思佳;陈乔;王海涛;刘钊杰
期刊:
华中师范大学学报(自然科学版) ,1992年(04):465-470 ISSN:1000-1190
作者机构:
华中师范大学化学系;华中师范大学有机所
关键词:
取代嘧啶;合成;胍;缩合;亲核取代反应
摘要:
采用胍与β-二羰基化合物缩合和嘧啶环上的亲核取代反应,合成了(a)~(p)共16个目标化合物,其中4个是新化合物,经改进合成方法和反应条件,使步骤简化或收率提高。产物结构经~1H NMR,IR和元素分析测试而确证。
语种:
中文
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DNA的↑(13)C化学位移与其链间嘌呤-嘌呤碰撞的相关性
作者:
张友杰;王可玉
期刊:
中国科学(B辑 化学 生命科学 地学) ,1991年(12):1259-1266 ISSN:1006-9240
作者机构:
[张友杰] 华中师范大学;[王可玉; Borer P N; Levy G C] 美国Sytacuse大学
关键词:
嘌呤-嘌呤碰撞;Calladine-Dickerson规则
摘要:
本文发现并间接证实了DNA的~(13)C化学位移与其结构参数(主轴螺旋扭曲角Ω,碱基平面滚动角ρ,主链扭曲角δ和螺旋浆式扭曲角ω)之间存在着相关性,文中阐明了与这些结构参数相关的碳及其理论上的解释。这些碳的化学位移相对变化明显地反映出DNA链间嘌呤-嘌呤碰撞(立体障碍)所引起的DNA双螺旋局部结构的变化,并与Calladine-Dickerson加和函数Σ作了比较。从DNA的~(13)C NMR谱可以得到有关其构象的信息,从而有可能通过~(13)C谱观测DNA在溶液中的Ω,ρ,δ和ω等结构参数。
语种:
中文
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三甲硅氧基烯丙基膦酸酯的合成
作者:
李中华;赵永镇;张景龄
期刊:
华中师范大学学报(自然科学版) ,1991年(01):62-65 ISSN:1000-1190
作者机构:
华中师范大学化学系;华中师范大学有机合成所
关键词:
硅基亚磷酸酯;磷酸酯;羰基化合物;加成反应;合成
摘要:
本文报导用二乙基三甲硅基亚磷酸醣与α,β-不饱和醛酮反应合成了六个三甲硅氧基烯丙基型膦酸酯。它们的结构经过IR、~1H NMR和MS分析证明,不同的反应物能选择性地发生1,2-加成或1,4加成,二者的比例决定于羰基化合物的结构。
语种:
中文
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Polarographic determination of fluoride using the adsorption wave of the Ce(III)-alizarin complexone-fluoride complex
作者:
LU, GH* ;LI, XM;HE, ZK;HU, SL
期刊:
Talanta ,1991年38(9):977-979 ISSN:0039-9140
通讯作者:
LU, GH
作者机构:
[LU, GH] Department of Chemistry, Central China Normal University, Wuhan, 430070, People's Republic of China
通讯机构:
[LU, GH] C;CENT CHINA NORMAL UNIV,DEPT CHEM,WUHAN 430070,PEOPLES R CHINA.
摘要:
A very sensitive electrochemical method for trace measurement of fluoride in water is discussed. The complex of cerium(III) with alizarin complexone (ALC) and fluoride ion is adsorbed at the dropping mercury electrode. In cathodic sweeps, the peak height is directly proportional to the concentration of fluoride over the range 8 x 10(-8)-5 x 10(-6)M (1.5 x 10(-9)-9.5 x 10(-8) g/ml), and the detection limit is 5 x 10(-8)M (9.5 x 10(-10) g/ml). The proposed method was applied to the determination of fluoride in water.
语种:
英文
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油茶皂素在光度分析中的应用研究——Ⅰ.5-Br-PADAP—金属—茶皂素体系
作者:
王建林;冯钰锜
期刊:
华中师范大学学报(自然科学版) ,1991年(02) ISSN:1000-1190
作者机构:
华中师范大学分析测试中心
关键词:
茶皂素;光度分析;2-(5-溴-2吡啶偶氮)-5二乙氨基酚
摘要:
本文报道了茶皂素对若干Me—5·Br-PADAP体系的影响,实验结果表明,茶皂素具有增溶、增敏作用。所测得波长及吸光度对研究茶皂素在分析中的应用具有参考价值。
语种:
中文
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MAXIMUM OVERLAP SYMMETRY ORBITALS
作者:
ZHAN, CG* ;ZHENG, F
期刊:
International Journal of Quantum Chemistry ,1991年39(5):729-746 ISSN:0020-7608
通讯作者:
ZHAN, CG
作者机构:
[ZHAN, CG; Fang Zheng; Chang-Guo Zhan Chang-Guo Zhan Chang-Guo Zhan; ZHENG, F] Department of Chemistry, Central China Normal University, Wuhan, 430070, People's Republic of China
通讯机构:
[ZHAN, CG] C;CENT CHINA NORMAL UNIV,DEPT CHEM,WUHAN 430070,PEOPLES R CHINA.
摘要:
Based on the principle of maximum overlap, a new simple method is suggested for constructing the symmetry orbitals of arbitrary molecules and the delocalized molecular orbitals of molecules that do not involve the rings with an odd number of atoms. All these orbitals, called “maximum overlap symmetry orbitals,” are determined by an extended maximum overlap criterion and form the bases for the irreducible representations of the molecular point symmetry group. The theoretical analysis and the numerical results show that the obtained molecular orbitals are close to those obtained from the customary LCAO method, and calculation by the proposed method requires less computing time than does the LCAO method, thus illustrating a fact that the method is not only a reasonable approximation of the LCAO method, but simpler and feasible in large molecular systems. Copyright © 1991 John Wiley & Sons, Inc.
语种:
英文
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The extremum method in quantum chemistry: Part II. Introduction to some applications
作者:
Frank Liu(Liu Fan)
期刊:
Computational and Theoretical Chemistry ,1991年230:47-65 ISSN:2210-271X
作者机构:
[Frank Liu(Liu Fan)] Department of Chemistry, Central China Normal University, Wuhan, 430070 People's Republic of China
摘要:
According to the differentiation method of the trace of matrices and the symmetric property of the squared matrix, L = BTPC, extremum approaches in some different fields were examined as examples. The examples examined were: Jug's method on bond order; Murrell's two theorems; Golebiewski's statement on the maximum overlap method of hybridization; Lykos and Schmeising's maximum overlap orbital; the derivation of the Roothaan's equation in the closed-shell or open-shell approach; and the natural expansion of the wavefunction and of the qth order reduced density matrix. The results indicate that the trace algebra, from which the differentiation method is constructed, will be an important and powerful tool in the future development of quantum chemistry.
语种:
英文
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新金属配位体1—羟基亚乙基二膦酸的合成与纯化
作者:
朱传方;张景龄;卢金桥
期刊:
化学试剂 ,1991年(2):125+78 ISSN:0258-3283
作者机构:
华中师范大学化学系有机合成所
关键词:
分析测定;正负离子;减压浓缩;合成;纯化方法;结晶法;金属离子;亚乙基;二膦酸;水溶液
摘要:
1-羟基亚乙基二膦酸(HEDP)在水溶液中可以离解成5个正负离子。HEDP 对金属具有相当强的螯合性,因此,它是一种重要的螯合剂。HEDP 与金属离子的螯合常数:Mg<sup>2+</sup>6.55,Ca<sup>2+</sup>6.04,Fe<sup>2+</sup>9.15,Fe<sup>3+</sup>16.21,Cu<sup>2+</sup>12.48,Zn<sup>2+</sup>10.37,Al<sup>3+</sup>11.29。此外,它还可与 Co、Ni、Pb、Sn、Sb 等进行螯合。可用来测定血和尿中 Ca<sup>2+</sup>的含量,废水中的 Zn,用极谱分析测定 Cu<sup>2+</sup>、Pb<sup>2+</sup>及 Co 和Ni。市场上一般都以50%左右的 HEDP 液体出售,主要用于防腐、缓蚀、阻垢。国外曾以强减压浓缩制得纯度在98%以上的 HED-P,有的是用加钠盐的方法进行纯化。近年
语种:
中文
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